A dental restoration may for various reasons be designed and manufactured for a patient's teeth. This dental restoration may e.g. provide that the size, shape and/or shade of the restored teeth is modified compared to the size, shape and/or shade of the existing teeth. This is e.g. the case when the height of the teeth has been reduced due to e.g. grinding the teeth in sleep (Sleep Bruxism), when a portion of a tooth is damaged, or when the patient wishes to improve the aesthetic appearance of his teeth.
When a tooth is damaged, such as when a portion of the tooth is broken off, the extent of the damage may be so that a crown restoration is required for the tooth. The damaged tooth is then prepared for the crown restoration by grinding away tooth material making space for the crown restoration. The prepared tooth is often referred to as a tooth stump since its size is significantly less than that of the unprepared tooth. However, in other cases the dentist may decide that the remaining portion of the tooth is sufficiently healthy such that there is no need for preparing the tooth to form a tooth stump ready for accepting a crown restoration. Still the broken off portion may be large enough to cause significant irritation. In such cases the dentist often decides to manufacture a dental restoration, such as a crown restoration, which is seated in the existing damaged tooth where the dental restoration preferably is designed to provide that the shape of the restored tooth is anatomically correct and does not cause irritation.
When a patient has worn his teeth down to an extent where the patient's normal occlusion is disrupted, the result may be that the patient begins to experience problems in his temporomandibular joint (TMJ). Such problems may be solved by seating a table-top restoration on the worn teeth, where the table-top restoration is shaped such that the occlusal surface and hence the bite of the restored teeth is raised and a correct movement of the TMJ is restored. The table-top restoration preferably has one or more teeth restorations covering at least the occlusal surface of the worn teeth, especially the occlusal surface of posterior teeth which has a large impact on TMJ problems. However the table-top restoration does not necessarily cover the entire labial/buccal and lingual surfaces of the patient's teeth.
CAD/CAM technology is frequently used in the manufacture of dental restorations, where the dental restoration is manufactured by milling the restoration from a blank based on a digital restoration design which expresses a planned shape of the dental restoration. In order for such a dental restoration to be capable of being seated at the patient's existing teeth, the inner surface of the restoration must either be shaped according to the current shape of the existing teeth or according to the egg-shell design where a large volume is provided for the existing teeth at the inner surface of the restoration. The first approach requires that the shape of the existing teeth is known with high precision from e.g. a scanning of the teeth, while the second approach results in a dental restoration which has no surfaces to rest on and thus is difficult to arrange precisely in the mouth.
It remains a problem to provide a method, a user interface, and a system for creating digital designs for use in manufacturing a molding-shell for use in the forming a dental restoration.
When such a molding-shell which is arranged at the patient's teeth where the molding-shell and the tooth surface together define a volume for the dental restoration. The molding-shell approach does not have the problem of how to shape the inner surface of the dental restoration described above.
Disclosed is a method for generating a digital design for use in the manufacture of a molding-shell for a patient's teeth, where the molding-shell and the teeth together enclose a volume for forming a dental restoration, where the method comprises:                obtaining a digital 3D representation of the patient's teeth, said digital 3D representation comprising a tooth part relating to one or more teeth for which the dental restoration is formed;        obtaining a set of one or more digital teeth anatomies;        arranging the set of digital teeth anatomies and the digital 3D representation according to a preferred relative arrangement; and        generating the digital design, where a first portion of the digital design is derived from the digital teeth anatomies and a second portion of the digital design is derived from the tooth part of the digital 3D representation.        
The enclosed volume is defined by part of an inner surface of the molding-shell and part of the surface of the existing teeth.
In the context of the present application, the phases “inner surface of the shell” and “inner shell surface” refers to a tooth facing surface of a digital 3D representation of the molding-shell, such as of a digital molding-shell design, or of a manufactured molding-shell. I.e. the inner shell surface may be the surface of a manufactured molding-shell which faces the patient's teeth when the molding-shell is arranged at the teeth.
The formed dental restoration is configured for being seated at the patient's existing teeth with an inner surface contacting/facing the existing teeth.
When the formed dental restoration is arranged at the patient's teeth, the shape of the restored tooth or teeth is at least partly determined by the shape of the dental restoration and partly by the portion of the tooth which is not covered by the dental restoration.
In the preferred relative arrangement the digital teeth anatomies and the digital 3D representation are arranged relative to each other according to an anatomical correct arrangement.
This provides the advantage that various digital operations, such as collision line detection and Boolean addition or subtraction, can be performed. Further it provides that the digital teeth anatomies can be visualized together with the digital 3D representation of the corresponding teeth, i.e. the teeth which the manufactured dental restoration(s) will be seated on.
When the manufactured molding-shell is arranged at the teeth, a dental material can be injected into the enclosed volume. The volume is shaped according to a planned shape of the dental restoration such that when the injected dental material has hardened, the formed dental restoration has the planned shape. The planned shape of the dental restoration is such that when the dental restoration is seated on the existing teeth, the restored teeth take the form of the target shape.
The first portion of the inner surface of the manufactured molding-shell defines part of the boundary of the enclosed volume such that the outer surface of the formed restoration is shaped according to this first portion.
The second portion of the inner surface of the manufactured molding-shell can engage the patient's existing teeth to provide support for the molding-shell at the teeth. For a table-top restoration the second portion contacts the surface of the existing teeth which the table-top restoration is formed for.
The shape of the dental restoration is determined in part from the shape of the digital teeth anatomies and in part from the preferred relative arrangement of the digital teeth anatomies and the digital 3D representation of the teeth. The digital teeth anatomies express a planned shape of the part of the patient's teeth covered by the manufactured dental restoration.
In the context of the present application, the phrase “restored tooth/teeth” is used in relation to the tooth/teeth-restoration ensemble formed when the dental restoration is seated at the patient's existing tooth/teeth.
The inner surface of the formed restoration, i.e. the restoration surface which faces/contacts the existing teeth, is shaped according to the part of the boundary of the enclosed volume defined by the surface of the existing teeth. This provides an advantage of the molding-shell approach in that an exact knowledge of the shape of the existing teeth is not required in order to form a dental restoration which easily can be seated at the teeth.
In some embodiments, the digital design comprises a digital diagnostic wax-up. The digital diagnostic wax-up is for the manufacture of a physical diagnostic wax-up, i.e. a physical diagnostic wax-up can be manufactured from the digital diagnostic wax-up using Computer Aided Manufacture (CAM) equipment for direct digital manufacture, such as 3D printing or milling. The digital diagnostic wax-up expresses the target shape of the restored teeth. Accordingly, the physical diagnostic wax-up produced from the digital diagnostic wax-up will be shaped according to the target shape of the restored teeth.
When a physical diagnostic wax-up is produced, the molding-shell can be manufactured by shaping a molding-shell material using the physical diagnostic wax-up. The inner surface of the molding-shell will then be defined by the physical diagnostic wax-up and will thus have a shape according to the target shape of the restored teeth.
Given that the second portion of the digital diagnostic wax-up is shaped as a tooth part of the digital 3D representation, the inner surface of the formed molding-shell can rest on the corresponding part of the patient's teeth, where the line of contact between the molding-shell and the surface of the existing teeth define the cervical boundary of the enclosed volume for the dental restoration.
In some embodiments, the digital design comprises a digital molding-shell design. The digital molding-shell design is for direct digital manufacture of the molding-shell, such that a physical molding-shell can be manufactured directly from the digital molding-shell design without the use of an intermediate physical model, such as a diagnostic-wax up. This provides that the overall process for designing and manufacturing the molding-shell requires at least one step less than methods in which an intermediate model is required.
In some embodiments, the first and second portions define an inner shell surface of the digital molding-shell design.
The inner shell surface then expresses the target shape of part of the restored tooth or teeth. When a dental restoration is formed using the molding-shell and subsequently seated on the teeth, the restored tooth or teeth will then have the target shape.
In some embodiments, generating the digital design comprises creating an outer shell surface of the digital molding-shell design.
The outer shell surface may at least partly be created by copying the inner shell surface and offsetting the copied surface outwards.
In some embodiments, generating the digital molding-shell design comprises creating a connecting surface configured for connecting the inner and outer shell surfaces of the digital molding-shell design to generate a solid digital structure for the digital molding-shell design. The physical molding-shell can be manufactured from such a solid digital structure using CAM equipment.
The connecting surface may be created by a loofting process.
In order to provide a steadier placement of the molding-shell at the patient's existing teeth, the molding-shell may be provided with support structures that engage surfaces of the existing teeth to provide support for the molding-shell. The support structures may also aid the dentist when he arranges the molding-shell at the patient's teeth to ensure that the molding-shell is arranged correctly.
In some embodiments, the method comprises adding one or more digital support structures to the digital molding-shell design, where the digital support structures extend from the inner shell surface to the tooth part of the digital 3D representation.
In the molding-shell manufactured from the digital molding-shell design, the corresponding physical support structures provides the support for steady and/or correct arrangement of the molding-shell relative to the existing teeth.
The one or more support structures on the digital molding-shell design can be formed by a Boolean addition of a digital structure which extends from the surface of the digital diagnostic wax-up to the tooth part of the digital 3D representation.
In some embodiments, the method comprises defining one or more holes in the digital diagnostic wax-up, where the holes extend from the surface of the digital diagnostic wax-up to the tooth part of the digital 3D representation.
When a molding-shell material is arranged both in one of these holes and on the surface of the diagnostic wax-up the material forms a coherent structure, where the part of the structure shaped according to the hole defines the support structure. In the manufactured molding-shell the support structure allows for a steadier placement of the molding-shell at the patient's existing teeth.
The one or more holes in the digital diagnostic wax-up can be formed by a Boolean subtraction of a digital structure which extends from the surface of the digital diagnostic wax-up to the tooth part of the digital 3D representation.
In the formed dental restoration, the holes introduced by the support structures of the manufactured molding-shell can be filled with the dental material after the molding-shell has been removed.
In some embodiments, the manufactured molding-shell comprises a channel extending from the inner shell surface to the outer shell surface. The channel is preferably located such that it's opening on the inner shell surface terminates at the first portion and thus faces the enclosed volume. The channel will then allow passage of the dental material to and from the enclosed volume. The dentist may then choose to inject the dental material into the enclosed volume though the channel while the molding-shell is arranged at the teeth. Also if the dentist prefers to fill the molding-shell with the dental material for the dental restoration prior to arranging the filled shell at the teeth, the channel will allow excess dental material to escape such that the formed dental restoration can take the shape of the enclosed volume. Dental material located in the channel may stick to the dental restoration but this can easily be grinded/polished off to provide a smooth surface of the dental restoration.
In some embodiments, the method comprises defining a channel in the digital molding-shell design, where the channel extends from the inner shell surface to the outer shell surface. The channel preferably contacts the inner surface at the first portion of the digital molding-shell design.
In a molding-shell manufactured from such a digital molding-shell design the corresponding channel allows passage of the dental material to and from the enclosed volume.
In some embodiments, the method comprises defining a protrusion on the digital diagnostic wax-up.
The protrusion is arranged such that it points outwards from the digital diagnostic wax-up.
The protrusion may be formed on the digital diagnostic wax-up by a Boolean addition of a digital representation of the protrusion and the digital diagnostic wax-up. Alternatively, the protrusion may be defined on the part of the digital teeth anatomies from which the first portion of the digital diagnostic wax-up is formed. This provides that when the digital diagnostic wax-up is generated, the protrusion is already formed on the digital diagnostic wax-up.
When a diagnostic wax-up manufactured from such a digital diagnostic wax-up is used for the manufacture of the molding-shell, the corresponding physical protrusion on the diagnostic wax-up will define the channel in the material of the molding-shell.
The protrusion can be said to be a negative of the channel.
In some embodiments, generating the digital design comprises a Boolean addition of the digital 3D representation and the set of digital teeth anatomies.
The Boolean addition provides a digital structure with a surface expressing the target shape of the restored teeth, where the digital structure has a portion corresponding to the digital teeth anatomies and a portion corresponding to the surface of the tooth/teeth for which the dental restoration is formed. This digital structure may potentially also comprise portions relating to neighboring teeth and/or soft tissue such as the surrounding gingiva.
In some embodiments, the method comprises determining a line of contact for the digital 3D representation and the set of digital teeth anatomies, wherein the line of contact is derived from an intersection of the digital 3D representation and the digital teeth anatomies.
Deriving the line of contact with the digital teeth anatomies and the digital 3D representation arranged according to the preferred relative arrangement provides that the generating of the digital design can be made highly automatic.
When arranged at the teeth, the manufactured molding-shell contacts the teeth at the contact line which then defines a margin line of the formed dental restoration.
In some embodiments, the first portion of the digital design is derived from a portion of the set of digital teeth anatomies coronal to the line of contact.
This provides that the first portion is shaped according to the set of digital teeth anatomies. The choice of digital teeth anatomies thus influences the shape of digital design and thereby the outer surface of the formed dental restoration. The operator can hence determine the shape of this portion of the dental restoration by his selection of digital teeth anatomies.
In some embodiments, the second portion of the digital design is derived from a portion of the digital 3D representation cervical to the line of contact.
This provides that the second portion is shaped according to the tooth part of the digital 3D representation cervical to the line of contact and that the manufactured molding-shell can rest on this portion of the existing teeth. I.e. the molding-shell contacts the surface of the tooth for which the restoration is formed.
In some embodiments, the digital design comprises a third portion derived from a portion of the digital 3D representation corresponding to neighboring teeth and/or soft tissue.
This provides the advantage that the manufactured molding-shell can have a section adapted for resting on the neighboring teeth and/or soft tissue, i.e. on the teeth surrounding the tooth/teeth for which the dental restoration is formed.
In some embodiments, the method comprises creating a digital restoration design for the dental restoration, where the digital restoration design expresses the planned shape of the dental restoration.
This provides the advantage that the digital restoration design can be visualized, optionally together with the patient's existing teeth, such that the operator can evaluate whether the planned shape of the dental restoration is adequate e.g. with respect to minimum thickness criteria and aesthetic properties.
In some embodiments, the digital restoration design is created based on the digital teeth anatomies and the digital 3D representation of the patient's teeth when these are arranged according to the preferred relative arrangement. E.g. the digital restoration design is created can be created by a Boolean subtraction of the digital 3D representation of the patient's teeth from the digital teeth anatomies.
The digital restoration design may comprise a restoration margin line. In some embodiments, the restoration margin line is derived from the line of contact between the digital teeth anatomies and the digital 3D representation of the patient's teeth. The restoration margin line can thus be determined automatically without the need for the operator to use time to manually define it.
The digital restoration design may be designed to improve the aesthetics and function of the patient's set of teeth. With respect to the function it can be advantageous to analyze the bite of the patient's restored teeth using a virtual articulator which mimics the relative movements of the patient's jaws during a bite.
In some embodiments, an inner restoration surface of the dental restoration design is shaped according to portions of the existing teeth coronal to the line of contact while the outer surface of the dental restoration is shaped according to the digital teeth anatomies.
In some embodiments, at least part of the first portion of the digital design is created from the digital restoration design.
Given that the digital restoration design is crated from the digital teeth anatomies, this provides that first portion of the digital design is derived from the digital teeth anatomies.
In some embodiments the molding-shell is for forming a table-top restoration, an onlay, an inlay, a crown, a bridge, or a veneer, such as a minimum-preparation veneer.
The dental restoration may be a table-top restoration configured for raising the patient's bite. Table-top restorations are frequently used when the occlusal table of the patient's teeth is severely worn. The table-top restoration is shaped to be seated on top of the teeth where it raises the patient's bite. There is hence no need for preparing the tooth by grinding away substantial amounts of tooth material and the second portion of the digital design can be defined from a tooth part of a digital 3D representation of the patent's teeth. The same is true for the so-called minimum-preparation veneers which comprise a relatively thin layer of restoration material shaped to cover part of the labial and buccal surfaces of the teeth in order to improve the aesthetics of the teeth.
The table-top teeth can be a temporary restoration worn by the patient for a period of time in which period the patient's muscles are trained for the raised bite. This may be applicable to patients having problems with the temporomandibular joint (TMJ) and where the occlusal surface of e.g. the teeth of the mandibular jaw must be raised to treat the problem. After a period of time, e.g. some months, the dentist evaluates whether the raised bite is appropriate and solves the TMJ problems.
When the patient is not pleased with the appearance of his teeth he may wish to have a veneer designed and manufactured for his teeth. The patient may still have all his teeth in their original and unprepared shape but desires a more appealing smile. A veneer is often designed and manufactured for the anterior teeth which are the most visible of the patient's teeth.
In some embodiments the digital design is for the manufacture of a molding-shell for a minimum-preparation veneer.
The dental restoration may be a crown restoration for a damaged tooth, where the crown is configured for being seated at a slightly prepared tooth.
Deriving the intersection of the digital 3D representation and the digital teeth anatomies and detecting the line of contact from the intersection are preferably performed by computer implemented algorithms executed on e.g. a microprocessor. This provides the advantage that the operator does not need to manually define the line of contact and the design process can be accelerated. This advantage is obtained when the manufactured dental restoration is to be arranged on a patient's existing tooth/teeth. In contrast, when the dental restoration is e.g. a crown for a fully prepared tooth a restoration margin line must be defined for the crown, where the restoration margin line precisely must match the preparation line of the prepared tooth in order to avoid e.g. a grove at the transition between the dental restoration and the prepared tooth causing discomfort and the risk of bacteria being caught.
In some cases the operator may choose to make slight modifications to the line of contact but this is often not required. An example of such a modification is the smoothing of the line of contact to provide a smooth transition between the first and second portions of the digital design, such that e.g. the diagnostic wax-up or the molding-shell is easier to manufacture from the digital design. The digital design may be modified in response to such a modification, e.g. by making slight changes in the parts of the digital teeth anatomies and the tooth part of the digital 3D representation used in forming the first and second portions of the digital design. In some cases it may be necessary to apply a loofting process to connect the modified first and second portions of the digital design to form complete and watertight digital design.
The determined line of contact divides the digital teeth anatomies into a coronal part and a cervical/apical part, where the coronal part forms the first portion of the generated digital design. In some embodiments, the method comprises digitally removing portions of the digital teeth anatomies cervical/apical to the line of contact and using the thus truncated digital teeth anatomies in generating the digital design.
In the context of the present invention, the phrase “Item 1 being coronal to Item 2” refers to the situation where Item 1 is closer to the occlusal surface/incisal edge of a tooth than Item 2. In the context of the present invention, the phrase “Item 1 being cervical/apical to Item 2” refers to the situation where Item 1 is closer to the root part of the tooth, i.e. where item 2 is closer to the occlusal surface/incisal edge of a tooth than Item 1.
The line of contact separates the coronal and cervical portions of the tooth part of the digital 3D representation. In some embodiments, the method comprises digitally removing portions of the digital 3D representation coronal to the line of contact and using the thus truncated digital 3D representation as the second portion in creating the digital design.
The inner and outer surfaces of a digital restoration design may be based on coronal portions of the digital 3D representation and of the digital teeth anatomies, respectively, where the coronal portions may be bounded by the determined line of contact.
In some embodiments, creating the first and second portions of the digital design comprises copying the corresponding sections of the digital teeth anatomies and of the tooth part of the digital 3D representation. The copied sections may further be modified according to the operators experience and preferences.
In some embodiments, the sections of the digital teeth anatomies and of the tooth part of the digital 3D representation which are used in generating the digital restoration design are coronal to the detected line of contact such that determined line of contact defines a restoration margin line for the formed dental restoration.
In some embodiments, creating the digital restoration design comprises a Boolean subtraction of the digital 3D representation from the digital teeth anatomies.
The intersection of the digital 3D representation and the digital teeth anatomies is automatically defined in the Boolean subtraction. Creating the digital restoration design by such a Boolean subtraction has the advantage that the restoration margin line is automatically derived. The shape and position of the restoration margin line depends on the digital teeth anatomies, the digital 3D representation and the preferred relative arrangement.
A Boolean subtraction of a first solid digital structure from a second solid digital structure provides that a third solid digital structure is generated where the third solid digital structure is shaped according to the second solid digital structure where the parts shared with the first solid digital structure are removed.
The Boolean subtraction of the solid digital structures may correspond to determining their relative complement, such that the digital restoration design resulting from the Boolean subtraction is the part of the digital teeth anatomies which is not shared with the digital 3D representation. Thereby the created inner surface of the digital restoration design is shaped according to the shape of the corresponding part of the digital 3D representation while the outer surface of the digital restoration design is shaped according to the shape of the digital teeth anatomies. The inner surface of the digital restoration design is thus at least in part created by determining the relative complement of the digital 3D representation in the digital teeth anatomies.
The distance between a point on the first portion of the digital design and the nearest point on the digital 3D representation provides a measure of the planned thickness of the formed dental restoration at this point. Alternatively, the planned thickness can be measured from the digital teeth anatomies to the digital 3D representation. I.e. in some embodiments, the method comprises determining a planned thickness of the dental restoration as the distance from the digital 3D representation of the patient's teeth to the digital design or to the digital teeth anatomies
In some embodiments, the method comprises examining the planned thickness with respect to one or more minimum thickness criteria to identify any problematic regions.
In some embodiments, the method comprises examining the digital restoration design with respect to one or more minimum thickness criteria to identify any problematic regions of the dental restoration.
A problematic region may be a region of the digital design where the planned thickness is below that specified by the minimum thickness criteria. In the formed dental restoration the corresponding region will be so thin that the dental restoration may be fragile.
Examining the planned thickness with respect to one or more minimum thickness criteria provides the advantage that the operator can be warned that the current shape of the digital design will provide a fragile dental restoration.
In some embodiments the method comprises adjusting the first portion of the digital design in the problematic regions to provide that the minimum thickness criteria are met in these regions.
This has the advantage that the formed dental restoration will be robust and have no fragile regions.
In some embodiments the adjusting comprises:                modifying the first portion such that the planned thickness is increased in the problematic region and the minimum thickness criteria are met; and/or        extending the second portion of the digital design to a point where the minimum thickness criteria are met and truncating the first portion accordingly.        
Both increasing the planned thickness and extending the second portion in the problematic region provide the advantage that the formed dental restoration is free of problematic regions causing fragile regions where it otherwise may break easily.
In some embodiments the method comprises defining an offset surface by offsetting at least part of the digital 3D representation a distance according to the minimum thickness criteria. The offset is directed outwards relative to the surfaces of the digital 3D representation. For instance if a minimum thickness criterion dictates a minimum thickness of 0.5 mm the offset surface can be formed by offsetting the surface of the digital 3D representation outwards by 0.5 mm. The value of this number may depend on the dental material used for forming the dental restoration.
The offset surface can be used when examining the first portion of the digital design and/or the digital restoration design to identify problematic regions where the minimum thickness criteria are not fulfilled. This can be realized by identifying the portions of the first portion or of the digital teeth anatomies which are located between the digital 3D representation and the offset surface. Such portions will not fulfill the minimum thickness criteria.
If problematic regions are found, the offset surface can be used for the adjustment of the first portion of the digital design such as by modifying it to follow the offset surface at least in part of the problematic regions. The problematic regions of the first portion can e.g. be snapped onto the offset surface, i.e. shaped to follow the offset surface, whereby it is provided that the planned thickness is increased to a level where the minimum thickness criteria also are fulfilled in those regions.
The offset surface can also be used to determine the point where the minimum thickness criteria are met, such that the second portion of the digital design can be extended to this to provide that the minimum thickness criteria are fulfilled for all regions. This point may be where the offset surface intersects the digital teeth anatomies.
In some embodiments the digital restoration design is for manufacture of the molding-shell by milling and the method comprises adjusting the digital design to provide for drill compensation.
In the context of the present invention, the phrase “to provide for drill compensation” refers to the case where the digital design is adjusted such that the shape of the drill which is to be used is taken into consideration.
When the tip of the drill has a curvature it cannot form e.g. a 90 degrees bend. When attempting to form sharp bends some material will be remaining. For a molding-shell with an inner surface shaped according to a planned shape of the dental restoration this remaining material may cause that a section of the formed dental restoration is missing.
In some embodiments the drill compensation is provided by introducing one or more indentations in the digital design e.g. where a support structure raises from the first portion of a digital molding-shell design. The indentations will cause that the inner surface of the manufactured molding-shell has indentations and accordingly that protrusions are defined on the surface of the formed dental restoration. The excess restoration material can however be grinded and/or polished away such that the final dental restoration is shaped according to the planned shape.
In some embodiments, the cross-sectional size of the indentation is chosen to be larger than or equal to the diameter of the drill which is to be used in the manufacture of the dental restoration. For an indentation with a circular cross-section, the cross sectional size is the diameter of the indentation.
In some embodiments the method comprises adjusting the curvature of the digital design at the line of contact to match the curvature of the digital 3D representation of the patient's teeth.
A large mismatch in curvature can make the interface between the dental restoration and the existing teeth clearly visible. The curvature adjustment may provide a smoother and less visible transition from teeth to dental restoration and thus improve the appearance of the restored tooth/teeth.
In some embodiments obtaining the digital teeth anatomies comprises selecting a set of library teeth.
This has the advantage that the digital teeth anatomies can be obtained faster than when the operator himself designs the surfaces of the digital teeth anatomies.
Disclosed is a method for generating a digital design for use in the manufacture of a molding-shell for a patient's teeth, where the molding-shell and the teeth together enclose a volume for forming a dental restoration, where the method comprises:                loading a digital 3D representation of the patient's teeth into an electronic data processing device, said digital 3D representation comprising a tooth part relating to one or more teeth for which the dental restoration is formed;        loading a set of one or more digital teeth anatomies into the electronic data processing device;        arranging the set of digital teeth anatomies and the digital 3D representation according to a preferred relative arrangement; and        using said electronic data processing device to execute computer implemented algorithms configured for generating the digital design where a first portion of the digital design is derived from the digital teeth anatomies and a second portion of the digital design is derived from the tooth part of the digital 3D representation.        
The electronic data processing device can be a computer processor such as a microprocessor.
Disclosed is a user interface for generating a digital design for use in the manufacture of a molding-shell for a patient's teeth, where the molding-shell and the teeth together enclose a volume for forming a dental restoration, where the user interface is configured for:                obtaining a digital 3D representation of the patient's teeth, said digital 3D representation comprising a tooth part relating to one or more teeth for which the dental restoration is formed;        obtaining a set of one or more digital teeth anatomies;        arranging the set of digital teeth anatomies and the digital 3D representation according to a preferred relative arrangement; and        generating the digital design where a first portion of the digital design is derived from the digital teeth anatomies and a second portion of the digital design is derived from the tooth part of the digital 3D representation.        
In some embodiments, the user interface comprises a virtual push button configured for generated the digital design when activated.
The digital design can be generated using a method according to any of the embodiments. For example the digital design can be a digital diagnostic wax-up generated by a Boolean addition of the digital teeth anatomies and the tooth part of the digital 3D representation.
In some embodiments, the user interface is configured for being visualized to an operator using a visual display unit and for allowing an operator to enter data into and make choices presented in the user interface by means of a computer keyboard or a computer mouse.
In some embodiments, the user interface comprises a data entering section for entering data relating to e.g. whether the generated digital design shall be a digital molding-shell design or a digital diagnostic wax-up, and whether the digital design is to be created from a determined line of contact or by a Boolean addition.
In some embodiments, the user interface is configured for visualizing the created digital design.
Disclosed is a method for manufacturing a molding-shell for a patient's teeth, where the molding-shell and the teeth together enclose a volume for forming a dental restoration, where the method comprises:                generating a digital design using a method according to any of the embodiments, and        manufacturing a physical copy of the digital design using direct digital manufacture equipment.        
In some embodiments, the digital design comprises a digital diagnostic wax-up such that the manufactured physical copy comprises a physical diagnostic wax-up, and the method comprises arranging a molding-shell material at the manufactured physical diagnostic wax-up such that the molding-shell is manufactured with an inner surface shape defined by the physical diagnostic wax-up.
In some embodiments, the digital design comprises a digital molding-shell design such that the physical copy manufactured from the digital design comprises the molding-shell.
Disclosed is a method for manufacturing a molding-shell for a patient's teeth, where the molding-shell and the teeth together enclose a volume for forming a dental restoration, where the method comprises:                obtaining a digital 3D representation of the patient's teeth, said digital 3D representation comprising a tooth part relating to one or more teeth for which the dental restoration is formed;        obtaining a set of one or more digital teeth anatomies;        arranging the set of digital teeth anatomies and the digital 3D representation according to a preferred relative arrangement; and        generating the digital design where a first portion of the digital design is derived from the digital teeth anatomies and a second portion of the digital design is derived from the tooth part of the digital 3D representation.        
In some embodiments, the digital design comprises a digital diagnostic wax-up and the method comprises manufacturing a physical diagnostic wax-up from the digital diagnostic wax-up and arranging a molding-shell material at the manufactured physical diagnostic wax-up, such that the molding-shell is manufactured with an inner surface shape defined by the physical diagnostic wax-up.
In some embodiments, the digital design comprises a digital molding-shell design where the first and second portions define an inner shell surface of the digital molding-shell design, and the method comprises:                forming a solid digital structure for the digital molding-shell design based at least partly on the inner shell surface, and        manufacturing the molding-shell from the solid digital structure.        
Disclosed is a method for generating a digital design for use in the manufacture of a molding-shell for a patient's teeth, where the molding-shell and the teeth together enclose a volume for forming a dental restoration, where the method comprises:                obtaining a digital 3D representation of the patient's teeth, said digital 3D representation comprising a tooth part relating to one or more teeth for which the dental restoration is formed;        designing a digital restoration design at the digital 3D representation where the digital restoration design express a planned shape of the dental restoration; and        generating the digital design, where a first portion of the digital design is derived from the digital restoration design and a second portion of the digital design is derived from the tooth part of the digital 3D representation.        
In some embodiments, obtaining the digital 3D representation of the patient's teeth comprises loading the digital 3D representation into an electronic data processing device and generating the digital design comprises executing computer implemented algorithms on the electronic data processing device, where the algorithms are configured for generating the digital design at least partly from the digital 3D representation of the patient's teeth and the digital restoration design.
Disclosed is a user interface for generating a digital design for use in the manufacture of a molding-shell for a patient's teeth, where the molding-shell and the teeth together enclose a volume for forming a dental restoration, where the user interface is configured for:                obtaining a digital 3D representation of the patient's teeth, said digital 3D representation comprising a tooth part relating to one or more teeth for which the dental restoration is formed;        designing a digital restoration design at the digital 3D representation where the digital restoration design express a planned shape of the dental restoration; and        generating the digital design, where a first portion of the digital design is derived from the digital restoration design and a second portion of the digital design is derived from the tooth part of the digital 3D representation.        
Disclosed is a system for designing a digital design for manufacturing a molding-shell for a patient's teeth, where the molding-shell and the teeth together enclose a volume for forming a dental restoration, wherein the system comprises:                a computer device comprising a non-transitory computer readable medium and an electronic data processing device, where said computer device is capable of obtaining a set of one or more digital teeth anatomies and a digital 3D representation of the patient's teeth, where said digital 3D representation comprises a tooth part relating to one or more teeth for which the dental restoration is formed;        a visual display unit for displaying the digital teeth anatomies and the digital 3D representation of the patient's teeth; and        digital tools allowing an operator to arrange the set of digital teeth anatomies and the digital 3D representation according to a preferred relative arrangement;where the computer readable medium comprises computer code which when executed on the electronic data processing device generates the digital design, where a first portion of the digital design is derived from the digital teeth anatomies and a second portion of the digital design is derived from the tooth part of the digital 3D representation.        
Disclosed is a system for designing a digital design for manufacturing a molding-shell for a patient's teeth, where the molding-shell and the teeth together enclose a volume for forming a dental restoration, wherein the system comprises:                a computer device comprising a non-transitory computer readable medium and an electronic data processing device, where said computer device is capable of obtaining a digital 3D representation of the patient's teeth, where said digital 3D representation comprises a tooth part relating to one or more teeth for which the dental restoration is formed;        a visual display unit for displaying the digital 3D representation of the patient's teeth and a digital restoration design expressing a planned shape of the dental restoration; and        digital tools allowing an operator to design the digital restoration design at the digital 3D representation;where the computer readable medium comprises computer code which when executed on the electronic data processing device generates the digital design, where a first portion of the digital design is derived from the digital restoration design and a second portion of the digital design is derived from the tooth part of the digital 3D representation.        
As described above the digital design may be for direct digital manufacture of the structure described by the digital design using CAM equipment.
When the digital design is a digital molding-shell design the molding shell is preferably manufactured directly from the digital design by the system. The digital design may also be for manufacture of a diagnostic wax-up expressing a target shape of the restored teeth such that the molding-shell is formed by applying molding-shell material to the surface of the manufactured diagnostic wax-up.
The digital tools of the system may comprise a pointing tool, such as a computer mouse, and a keyboard.
When a direct digital manufacture unit, such as CAM equipment, is included in the system it can be used as a system for manufacturing the molding-shell for a patient's teeth.